/* example.c -- usage example of the zlib compression library
 * Copyright (C) 1995-2004 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* @(#) $Id$ */

#include <stdio.h>
#include "zlib.h"

#ifdef STDC
	#include <string.h>
	#include <stdlib.h>
#endif

#if defined(VMS) || defined(RISCOS)
	#define TESTFILE "foo-gz"
#else
	#define TESTFILE "foo.gz"
#endif

#define CHECK_ERR(err, msg) { \
    if (err != Z_OK) { \
        fprintf(stderr, "%s error: %d\n", msg, err); \
        exit(1); \
    } \
}

const char hello[] = "hello, hello!";
/* "hello world" would be more standard, but the repeated "hello"
 * stresses the compression code better, sorry...
 */

const char dictionary[] = "hello";
uLong dictId; /* Adler32 value of the dictionary */

void test_compress      OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
void test_gzio          OF((const char* fname,
                            Byte* uncompr, uLong uncomprLen));
void test_deflate       OF((Byte* compr, uLong comprLen));
void test_inflate       OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
void test_large_deflate OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
void test_large_inflate OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
void test_flush         OF((Byte* compr, uLong* comprLen));
void test_sync          OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
void test_dict_deflate  OF((Byte* compr, uLong comprLen));
void test_dict_inflate  OF((Byte* compr, uLong comprLen,
                            Byte* uncompr, uLong uncomprLen));
int  main               OF((int argc, char* argv[]));

/* ===========================================================================
 * Test compress() and uncompress()
 */
void test_compress(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	int err;
	uLong len = (uLong)strlen(hello) + 1;

	err = compress(compr, &comprLen, (const Bytef*)hello, len);
	CHECK_ERR(err, "compress");

	strcpy((char*)uncompr, "garbage");

	err = uncompress(uncompr, &uncomprLen, compr, comprLen);
	CHECK_ERR(err, "uncompress");

	if(strcmp((char*)uncompr, hello)) {
		fprintf(stderr, "bad uncompress\n");
		exit(1);
	} else {
		printf("uncompress(): %s\n", (char*)uncompr);
	}
}

/* ===========================================================================
 * Test read/write of .gz files
 */
void test_gzio(fname, uncompr, uncomprLen)
const char* fname; /* compressed file name */
Byte* uncompr;
uLong uncomprLen;
{
#ifdef NO_GZCOMPRESS
	fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
#else
	int err;
	int len = (int)strlen(hello) + 1;
	gzFile file;
	z_off_t pos;

	file = gzopen(fname, "wb");

	if(file == NULL) {
		fprintf(stderr, "gzopen error\n");
		exit(1);
	}

	gzputc(file, 'h');

	if(gzputs(file, "ello") != 4) {
		fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
		exit(1);
	}

	if(gzprintf(file, ", %s!", "hello") != 8) {
		fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
		exit(1);
	}

	gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
	gzclose(file);

	file = gzopen(fname, "rb");

	if(file == NULL) {
		fprintf(stderr, "gzopen error\n");
		exit(1);
	}

	strcpy((char*)uncompr, "garbage");

	if(gzread(file, uncompr, (unsigned)uncomprLen) != len) {
		fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
		exit(1);
	}

	if(strcmp((char*)uncompr, hello)) {
		fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
		exit(1);
	} else {
		printf("gzread(): %s\n", (char*)uncompr);
	}

	pos = gzseek(file, -8L, SEEK_CUR);

	if(pos != 6 || gztell(file) != pos) {
		fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
		        (long)pos, (long)gztell(file));
		exit(1);
	}

	if(gzgetc(file) != ' ') {
		fprintf(stderr, "gzgetc error\n");
		exit(1);
	}

	if(gzungetc(' ', file) != ' ') {
		fprintf(stderr, "gzungetc error\n");
		exit(1);
	}

	gzgets(file, (char*)uncompr, (int)uncomprLen);

	if(strlen((char*)uncompr) != 7) {  /* " hello!" */
		fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
		exit(1);
	}

	if(strcmp((char*)uncompr, hello + 6)) {
		fprintf(stderr, "bad gzgets after gzseek\n");
		exit(1);
	} else {
		printf("gzgets() after gzseek: %s\n", (char*)uncompr);
	}

	gzclose(file);
#endif
}

/* ===========================================================================
 * Test deflate() with small buffers
 */
void test_deflate(compr, comprLen)
Byte* compr;
uLong comprLen;
{
	z_stream c_stream; /* compression stream */
	int err;
	uLong len = (uLong)strlen(hello) + 1;

	c_stream.zalloc = (alloc_func)0;
	c_stream.zfree = (free_func)0;
	c_stream.opaque = (voidpf)0;

	err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
	CHECK_ERR(err, "deflateInit");

	c_stream.next_in  = (Bytef*)hello;
	c_stream.next_out = compr;

	while(c_stream.total_in != len && c_stream.total_out < comprLen) {
		c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
		err = deflate(&c_stream, Z_NO_FLUSH);
		CHECK_ERR(err, "deflate");
	}

	/* Finish the stream, still forcing small buffers: */
	for(;;) {
		c_stream.avail_out = 1;
		err = deflate(&c_stream, Z_FINISH);

		if(err == Z_STREAM_END) break;

		CHECK_ERR(err, "deflate");
	}

	err = deflateEnd(&c_stream);
	CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with small buffers
 */
void test_inflate(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	int err;
	z_stream d_stream; /* decompression stream */

	strcpy((char*)uncompr, "garbage");

	d_stream.zalloc = (alloc_func)0;
	d_stream.zfree = (free_func)0;
	d_stream.opaque = (voidpf)0;

	d_stream.next_in  = compr;
	d_stream.avail_in = 0;
	d_stream.next_out = uncompr;

	err = inflateInit(&d_stream);
	CHECK_ERR(err, "inflateInit");

	while(d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
		d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
		err = inflate(&d_stream, Z_NO_FLUSH);

		if(err == Z_STREAM_END) break;

		CHECK_ERR(err, "inflate");
	}

	err = inflateEnd(&d_stream);
	CHECK_ERR(err, "inflateEnd");

	if(strcmp((char*)uncompr, hello)) {
		fprintf(stderr, "bad inflate\n");
		exit(1);
	} else {
		printf("inflate(): %s\n", (char*)uncompr);
	}
}

/* ===========================================================================
 * Test deflate() with large buffers and dynamic change of compression level
 */
void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	z_stream c_stream; /* compression stream */
	int err;

	c_stream.zalloc = (alloc_func)0;
	c_stream.zfree = (free_func)0;
	c_stream.opaque = (voidpf)0;

	err = deflateInit(&c_stream, Z_BEST_SPEED);
	CHECK_ERR(err, "deflateInit");

	c_stream.next_out = compr;
	c_stream.avail_out = (uInt)comprLen;

	/* At this point, uncompr is still mostly zeroes, so it should compress
	 * very well:
	 */
	c_stream.next_in = uncompr;
	c_stream.avail_in = (uInt)uncomprLen;
	err = deflate(&c_stream, Z_NO_FLUSH);
	CHECK_ERR(err, "deflate");

	if(c_stream.avail_in != 0) {
		fprintf(stderr, "deflate not greedy\n");
		exit(1);
	}

	/* Feed in already compressed data and switch to no compression: */
	deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
	c_stream.next_in = compr;
	c_stream.avail_in = (uInt)comprLen / 2;
	err = deflate(&c_stream, Z_NO_FLUSH);
	CHECK_ERR(err, "deflate");

	/* Switch back to compressing mode: */
	deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
	c_stream.next_in = uncompr;
	c_stream.avail_in = (uInt)uncomprLen;
	err = deflate(&c_stream, Z_NO_FLUSH);
	CHECK_ERR(err, "deflate");

	err = deflate(&c_stream, Z_FINISH);

	if(err != Z_STREAM_END) {
		fprintf(stderr, "deflate should report Z_STREAM_END\n");
		exit(1);
	}

	err = deflateEnd(&c_stream);
	CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with large buffers
 */
void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	int err;
	z_stream d_stream; /* decompression stream */

	strcpy((char*)uncompr, "garbage");

	d_stream.zalloc = (alloc_func)0;
	d_stream.zfree = (free_func)0;
	d_stream.opaque = (voidpf)0;

	d_stream.next_in  = compr;
	d_stream.avail_in = (uInt)comprLen;

	err = inflateInit(&d_stream);
	CHECK_ERR(err, "inflateInit");

	for(;;) {
		d_stream.next_out = uncompr;            /* discard the output */
		d_stream.avail_out = (uInt)uncomprLen;
		err = inflate(&d_stream, Z_NO_FLUSH);

		if(err == Z_STREAM_END) break;

		CHECK_ERR(err, "large inflate");
	}

	err = inflateEnd(&d_stream);
	CHECK_ERR(err, "inflateEnd");

	if(d_stream.total_out != 2 * uncomprLen + comprLen / 2) {
		fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
		exit(1);
	} else {
		printf("large_inflate(): OK\n");
	}
}

/* ===========================================================================
 * Test deflate() with full flush
 */
void test_flush(compr, comprLen)
Byte* compr;
uLong* comprLen;
{
	z_stream c_stream; /* compression stream */
	int err;
	uInt len = (uInt)strlen(hello) + 1;

	c_stream.zalloc = (alloc_func)0;
	c_stream.zfree = (free_func)0;
	c_stream.opaque = (voidpf)0;

	err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
	CHECK_ERR(err, "deflateInit");

	c_stream.next_in  = (Bytef*)hello;
	c_stream.next_out = compr;
	c_stream.avail_in = 3;
	c_stream.avail_out = (uInt) * comprLen;
	err = deflate(&c_stream, Z_FULL_FLUSH);
	CHECK_ERR(err, "deflate");

	compr[3]++; /* force an error in first compressed block */
	c_stream.avail_in = len - 3;

	err = deflate(&c_stream, Z_FINISH);

	if(err != Z_STREAM_END) {
		CHECK_ERR(err, "deflate");
	}

	err = deflateEnd(&c_stream);
	CHECK_ERR(err, "deflateEnd");

	*comprLen = c_stream.total_out;
}

/* ===========================================================================
 * Test inflateSync()
 */
void test_sync(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	int err;
	z_stream d_stream; /* decompression stream */

	strcpy((char*)uncompr, "garbage");

	d_stream.zalloc = (alloc_func)0;
	d_stream.zfree = (free_func)0;
	d_stream.opaque = (voidpf)0;

	d_stream.next_in  = compr;
	d_stream.avail_in = 2; /* just read the zlib header */

	err = inflateInit(&d_stream);
	CHECK_ERR(err, "inflateInit");

	d_stream.next_out = uncompr;
	d_stream.avail_out = (uInt)uncomprLen;

	inflate(&d_stream, Z_NO_FLUSH);
	CHECK_ERR(err, "inflate");

	d_stream.avail_in = (uInt)comprLen - 2; /* read all compressed data */
	err = inflateSync(&d_stream);           /* but skip the damaged part */
	CHECK_ERR(err, "inflateSync");

	err = inflate(&d_stream, Z_FINISH);

	if(err != Z_DATA_ERROR) {
		fprintf(stderr, "inflate should report DATA_ERROR\n");
		/* Because of incorrect adler32 */
		exit(1);
	}

	err = inflateEnd(&d_stream);
	CHECK_ERR(err, "inflateEnd");

	printf("after inflateSync(): hel%s\n", (char*)uncompr);
}

/* ===========================================================================
 * Test deflate() with preset dictionary
 */
void test_dict_deflate(compr, comprLen)
Byte* compr;
uLong comprLen;
{
	z_stream c_stream; /* compression stream */
	int err;

	c_stream.zalloc = (alloc_func)0;
	c_stream.zfree = (free_func)0;
	c_stream.opaque = (voidpf)0;

	err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
	CHECK_ERR(err, "deflateInit");

	err = deflateSetDictionary(&c_stream,
	                           (const Bytef*)dictionary, sizeof(dictionary));
	CHECK_ERR(err, "deflateSetDictionary");

	dictId = c_stream.adler;
	c_stream.next_out = compr;
	c_stream.avail_out = (uInt)comprLen;

	c_stream.next_in = (Bytef*)hello;
	c_stream.avail_in = (uInt)strlen(hello) + 1;

	err = deflate(&c_stream, Z_FINISH);

	if(err != Z_STREAM_END) {
		fprintf(stderr, "deflate should report Z_STREAM_END\n");
		exit(1);
	}

	err = deflateEnd(&c_stream);
	CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with a preset dictionary
 */
void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
Byte* compr, *uncompr;
uLong comprLen, uncomprLen;
{
	int err;
	z_stream d_stream; /* decompression stream */

	strcpy((char*)uncompr, "garbage");

	d_stream.zalloc = (alloc_func)0;
	d_stream.zfree = (free_func)0;
	d_stream.opaque = (voidpf)0;

	d_stream.next_in  = compr;
	d_stream.avail_in = (uInt)comprLen;

	err = inflateInit(&d_stream);
	CHECK_ERR(err, "inflateInit");

	d_stream.next_out = uncompr;
	d_stream.avail_out = (uInt)uncomprLen;

	for(;;) {
		err = inflate(&d_stream, Z_NO_FLUSH);

		if(err == Z_STREAM_END) break;

		if(err == Z_NEED_DICT) {
			if(d_stream.adler != dictId) {
				fprintf(stderr, "unexpected dictionary");
				exit(1);
			}

			err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
			                           sizeof(dictionary));
		}

		CHECK_ERR(err, "inflate with dict");
	}

	err = inflateEnd(&d_stream);
	CHECK_ERR(err, "inflateEnd");

	if(strcmp((char*)uncompr, hello)) {
		fprintf(stderr, "bad inflate with dict\n");
		exit(1);
	} else {
		printf("inflate with dictionary: %s\n", (char*)uncompr);
	}
}

/* ===========================================================================
 * Usage:  example [output.gz  [input.gz]]
 */

int main(argc, argv)
int argc;
char* argv[];
{
	Byte* compr, *uncompr;
	uLong comprLen = 10000 * sizeof(int); /* don't overflow on MSDOS */
	uLong uncomprLen = comprLen;
	static const char* myVersion = ZLIB_VERSION;

	if(zlibVersion()[0] != myVersion[0]) {
		fprintf(stderr, "incompatible zlib version\n");
		exit(1);

	} else if(strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
		fprintf(stderr, "warning: different zlib version\n");
	}

	printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
	       ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());

	compr    = (Byte*)calloc((uInt)comprLen, 1);
	uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);

	/* compr and uncompr are cleared to avoid reading uninitialized
	 * data and to ensure that uncompr compresses well.
	 */
	if(compr == Z_NULL || uncompr == Z_NULL) {
		printf("out of memory\n");
		exit(1);
	}

	test_compress(compr, comprLen, uncompr, uncomprLen);

	test_gzio((argc > 1 ? argv[1] : TESTFILE),
	          uncompr, uncomprLen);

	test_deflate(compr, comprLen);
	test_inflate(compr, comprLen, uncompr, uncomprLen);

	test_large_deflate(compr, comprLen, uncompr, uncomprLen);
	test_large_inflate(compr, comprLen, uncompr, uncomprLen);

	test_flush(compr, &comprLen);
	test_sync(compr, comprLen, uncompr, uncomprLen);
	comprLen = uncomprLen;

	test_dict_deflate(compr, comprLen);
	test_dict_inflate(compr, comprLen, uncompr, uncomprLen);

	free(compr);
	free(uncompr);

	return 0;
}
